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The East Grand Boulevard roadway at the Corona (91) Freeway will remain closed and construction work will halt until Monday after a ramp's partial collapse left workers injured Friday. Melissa Etezadi reports for the NBC4 News at 7 p.m. (Published Saturday, Oct. 10, 2015)

The East Grand Boulevard roadway at the Corona (91) Freeway will remain closed and construction work will halt until Monday for officials to investigate the ramp's partial collapse that left workers injured Friday.

Nine workers were injured, three critically, late Friday night when the temporary support beams of the freeway ramp partially collapsed, officials said.

The collapse was reported about 11 p.m., according to the Riverside County Transportation Commission.

Part of an on-ramp was being lowered into place when the jacking operation failed, causing the bridge deck to drop about 16 inches and strike the temporary wooden support beams. Those beams hit workers and caused injury, according to a news release from the RCTC.

Workers Hurt in Partial Bridge Collapse on 91 Freeway

Up to 10 workers were hurt in a partial bridge collapse on the 91 Freeway in Corona. Melissa Etezadi reports for NBC4's Today in LA on Saturday, Oct. 10, 2015.

(Published Saturday, Oct. 10, 2015)

Kassandra Juarez, who was in the area at the time, said the collapse sounded "like a big boom. Like an earthquake - the ground started shaking."

The injured workers were taken to a hospital. One was released and three were hospitalized in critical condition.

"Our goal at this job is to our work safely so everyone goes home at the end of the day," said Jan Bohn, project manager. "That's a big deal for all of us. We failed yesterday."